I think Marcy Kennedy’s Deep Point of View (Busy Writer’s Guides Book 9) is the most “technical” book on the technique called “deep PoV” or “deep penetration third person” or “close third person.” The thing to keep in mind is that it’s a technique, just like showing, telling, passive voice, etc., not a type of viewpoint like First Person or Third Person. This book is very helpful in understanding narrative distance, i.e. how much inside a viewpoint character’s head you as a writer are placing a reader at any given point.

The The Emotion Thesaurus: A Writer’s Guide To Character Expression is also a good resource. Telling a reader that a character is scared/sad/angry/etc. is boring. Whenever possible, showing those emotions and letting the reader come to the conclusion, involves the reader in the story. He’s an active participant. This book not only gives you physical beats, but by combining physical (external and internal) beats with actions (also listed) it makes it easier to show. I have a saved search in Scrivener for emotion words. I used to run the search and then I look at whether or not it’s better to show rather than tell. I’ve done it often enough now that it’s become more automatic. Every once in awhile, when I’m stuck, I refer back to it, but not as much as I used to. Surprise! I can be taught.